Carburetor



/A/VENTOQ.' W/L/AM C. CARI/FR Y Mw@ PM ATTO/@wim Aug. 18, 1931;. w. c. CARTER CARBURETOR Filed July l5, 1927 Patented Aug. 18, 1931 UNITED STATES' PATENT oFFiCE '-WIILIAM C. CARTER, 0F FLINT, MICHIGAN CARBURTOB,

Application illed July 15, 1927. Serial No. 2.0.6,030.

exceptionally economical carburetor that is .luparticularly adapted for use on high speed,

-small bore, six-cylinder motors, such as `are now used extensively on automobiles.

Another Objectis to provide Aa carburetor t that will function as a small capacity carbu- -retor at ordinary running.. speeds` an'dfwillI function as a large capacity carburetor at vhigh speeds, is provided with a fixed liquid fuel supply jet or orifice.

l 2o lAnother object is to provide yaca'rburetor that is equipped with an accelerating well, and means whereby a.quick opening of the throttle will discharge the fuel from said Well suddenly aud'virtually dump said fuel into the main passageway, and a slow or gradual openin of the throttle will discharge thefuel from said well gradually and econom-l ically, through a path separate and 'distinct from that through which the fuel escapes throttle.. I

And still another obJect is to provide a carburetor of the kind above described .that 'i s easy to adjust, reliable in 'operationand inexpensive to manufacture. Other .objects and desirable features of -rny invention will be hereinafter pointed out. Y

To this end I have devised a carburetor that is equipped with a well for holding an accelerating charge of liquid fuelwhich is in readiness to be drawn into the main passage- Way of the carburetor in the event. the throttle valve is opened suddenly; a liquid fuel tube or. by-pass leading from a supply of` liquid fuel, preferably from the acceleratingwell, and ari-an ed with its upper end communicating with t e main passageway of the carburetor `at such a point that it will. supply fuel to said passageway at idle speeds an slow speeds, i. e., when the ithrottle valve is closed,

from the well on a sudden opening of the' oronly partly open; afuel supply device, preferably a nozzle provided with a fixed discharge orifice; an air chamber communicating with the main passageway of the carburetor and provided with a fixed air inlet; a plurality of siphoning devices for producing different degrees of suction on the fuel nozzle yaccording to the-` position of the throttle valve; a means for causing air tobe admitted to the stream of liquid fuel passing throughv the nozzle when the throttle ismoved into its wide o en position, thereby increasing the supply o fuel to the main passageway by speeding up the flow of the fuel through the nozzle, due to the fact that a stream com- `.posed ofliquid fuel and some air will travel notwithstanding the fact that it ata higher speed than a `solid stream of liquid fuel; and means for automatically increasing Vthe size of the opening between the air chamber and the main passageway when the speed `of travel of the stream of fuel discharging frein-the nozzle is speeded up or'increased by admitting air't said stream. l

A carburetor of the construction above del scribed virtually acts as a small. capacity carburetor at -ordinar running speeds, but when the throttle valve is movedintoitsliighspeed position, the suctibn ofthe ln nbitor caises the supply of fueland the s upply of air'to the main passageway to be increased to such an 30` I extent that the carburetor isconverted into a large capacity carburetor, notwithstanding the fact that the fuel nozzle is provided with a fixed orifice or jet. `The various elements thatmakeup thecarburetorcanbecoiistructed es and arranged in various ways without departing from the spirit of my invention, but I prefer` to 'locate theaccelerating well at the lower side ofthe air chamber in longitudinal alignment with the main passageway and arrange the fuel nozzle in said well so that it discharges upwardly towards said main air pasageway. A plurality of concentrically arranged, tubular members of different diameters are combined with the nozzle in such a way as to produce si honing devices that exert different degrees o suction on the nozzle at different stages of speed of the motor.

Figure 1 of the drawings is a vertical sec- 100 fit tional View of my improved carburetor, showing the throttle valve in its high speed or wide open position.

Figure 2 g tional view, showing the throttle valve in its closed position; and

Figure 3 is a sectional view, taken on'the line 3-3of Figure l.

In the acconipanying drawings which illustrate the *preferred form of my invention, embodied in a carburetor of similar design and embodying some of the features of the carburetor described in my pending application for Patent Serial No. 147,010, filed November 8, 1926, A designates the main passageway of the carburetor, which is arranged vertically, B designates the throttlevalve in said passageway, C designates an air chamber that communicates with the lower end of said main passageway, C designates a fixed air `inlet to said air chamber, D designates a conventional choke valve for the air chamber, Efdesignates the tioat chamber of the carburetor, F designates an'annular float in the float chamberthat surrounds a depending, hollowportion l on the body casting of the carburetor that constitutes an accelerating well G, and Hdesignatcs a needle valve that governs the admission of fuel to the float chamber from a source of supply of liquid fuel, said needle valve being preferably of triangular shape in cross section, as shown in Figure 3, and combined with an operating lever H that is adapted to be actuated by the loat F. .The carburetor is equipped with a fuel duct or by-pass that leads up wardly-from the accelerating well G and which is used to supply fuel to the main passageway A when the throttle valve is closed or only partly open. `Said fuel duct or bypass can be constructed in various ways, but it is preferably of the construction illustrated and described in my pending application previouslyj referred to and comprises an upper portion fornjied by a straight, Vertically-dis posed tube 2 that projects downwardly through the portion of the body casting in which the main passageway A is formed and terminates in a lug 3, the lower end of said fuel duct or by-pass being formed by a verT -tically-.disposed groove 4 in the exterior of a sleeve 5 that is snugly surrounded by the side wall of .the accelerating well G. The sleeve 5 is spaced away, slightly .from the bottom of said well and the lower end of the groove 4 is open, so that fuel can flow upwardly through said groove from the supply of fuel in the accelerating well.

The upper end portion of the fuel tube 2 is so constructed, formed or yarranged that when the throttle valve is closed or only partly'opcn, fuel will pass from the upper end of said tube into the passageway A at a point above the throttle valve and suflicient air will enter said tube from the passageway is a fragmentary vertical sec-' A at a point below the throttle valve to cut down or reduce the suction that is exerted on the upper end of thetube 2 by the high vacuum which then exists in the intake of\ the motor. Th'e'upper end portion of the tube 2 is alsodesigned so that the movement of the throttle valve forwardly, away from its idle position, cuts off the admission ofthe air that reduces the suction in said tube. thereby causing the full force of the suction which exists in the intake to become effective for drawing fuel upwardly through the tube 2. The result above described can be accomplished in various ways, but in the carburetor herein illustrated a hole 2a is formed in the side of the tube 2 at a point far enough below the upper -endof said tube to cause the hole 2a to be located below the throttle valve, as shown in Figure 2, willen said throttle valve is in its closed position. g

The lug 3 in which the lower end of the tube 2 is seated is provided with an air passageway 6 through which air is admitted to the lower end of the tube 2 from the air chamber C, and in order that the supply of air through said air passageway 6 may be regulated, an adjustable valve 7 is proyided for controlling the admission of air to the air passageway 6. Said air regulating valve 7 is herein illustrated as being provided with a stem having an externally-screw-threaded portion that is screwed into a hole in the lug 3 which communicates with the upper end of the fuel duct or groove 4'that leads upwardly from the accelerating well, and the valvev 7 is preferably provided with a spring or other suitable device S for retaining said valve in adjusted position. As shown in Figure l, the stem of the air Valve 7 is provided with a fuel duct 9 thathas a lateral outlet which constitutes a fuel supply orilice for the air passageway 6. When the engine is idling with the throttle valve set in its closed position, liquid fuel, mixed with air, will be drawn upwardly through the tube 2, and discharged from the upper end of said tube into'the main passageway A at a point above the throttle valve, due, of course, tothe fact that the vacuum inthe intake of the mol tor produces' a suction in the tube 2 that is ,exerted on the fuel duct or port 9 in the stem of the air valve 7. Notwithstamling the fact that the tube 2 establishes direct communication between the` intake of the motor and the fuel supply duct 9 in the. stein of the air valve when the throttle valve B is in its idle position, only a relatively slight suction exists inthe tube 2, because air is enteringthe lower end of said tubefrom the air passageway 6 and air is entering the upper end of said tube 2 through the lateral openfng 2a in said tube, which, at thisI time, is' located below the throttle valve. After the throttle -valve has been moved into such a. position valve is only partlyopen will become operative for drawing fuel upwardly through the tube 2,thus increasing the amount of fuel which said tube int-roduces'into the passageway A.

A fuel nozzle I,is arranged vertically at the centei of the accelerating well G with its discharge end directed upwardly towards the main passageway A, and a fuel duct or port` 10 of relatively large diameter is used to admit liquid fuel from-the float chamber `E to a center bore 11 in a plug 12 in the bottom of the accelerating well that carries the nozzle I, the duct or fuel passageway 18 of the 'nozzle I communicating with the center borel 11 inthe plug 12. A duct 14; of considerably less cross-sectional areathan the supply port- 10 is formed in the plug 12 in such a way that the upper end of said duct 14 communicates with the accfleratingwell G and the lovsgerl end of said duct communicates-with the' centei-'bore 11 in the plug previously referred to.

u u n u The nozzle Iis provided intermediate t.its

ends withfa transversely-disposed Aduct or cross duct 15 which establishes -comn'iunica- `tion between the accelerating well and the center passageway 13 of the nozzle, and below said duct is a contracted portion 13 whoseL lower end or inlet end is Hai-ed at 13"` so as to overcome the tendency; of said .contracted portion to clog, ashereinafter clescribed. `The fuel in the float chamber E normally stands broken line m in Figure 1, and thercis normally an accelerating charge in the well G thatY is in readiness vto be drawn into the main passageway A of the carburetoi in the event the throttle valve is opened suddenly. v

Normally, the duct 14 functions asl a fuel supply duct to, admit liquid fuel to the ac- 12, the weight of the fuel vin the flat'chamber causing the wardly into the accelerating well through the duct 14. As the speed of `the motor increases, the suction in the bore 11 increases,

and when the suction in said bore 11 balancesv at thelevel indicated by the. accordingly, w

fuel to pass upwardly throughv the port 10 into the bore 11, and thence-apk tubular siphoning devices, previously referred'to, that are combined with the nozzle I so as to exert different degrees of suction on said nozzle in different positions of the throttle valve, are herein illustrated as being formed by a tubular member J, preferably of Venturi form, projecting upwardly from the bottom of the accelerating well in concentric relation with the fuel nozzle I and arranged with its contracted portion located adjacent ,the upper end of said nozzle, a second tubular member K attached to the 'upper en'd of the-'sleeve 5 in the accelerating well, and preferably shaped so as to form a yVenturi whose contracted portions surrounds tlie upper end of the tubular member J, and a third tubular member L, preferably'of Venturi'form, arranged in the main passageway A with its contracted portion normally positioned in close proximity to the upper end of the tubular member K. Vliile I (prefer to make said tubular members of Venturi form, this is not essential, so long :is a bottom tubular member-is `combined with p the upper eiid portion of the Afuel nozzle I in such a `way as to form an annular passageway up through which air will rush, and thus create` a suction on the upper end of the fuel forni' a second annular passageway up through-which air rushes, thus creating .a strong suction inside of the first tubular member-,tand -a third or top tubular member is .l con'ibincd with the upper, portion of the intermediate tubular member insuch a way as to formf an annular passageway up through i which '-a'ir' rushes, and thus creates, a 'strong suction inside of the second tubular member.4 The tubular member L, referred to above yas the third or top member, lis'inounted in the main passageway-A in such 1`amanner celerating well from the bore 11 in the Plug' that 1t' 1S capable of movmg vertl'cauy .relai tively to the tubular member K, so as to vary thesize of the annularppening between the contracted portion of the memberL and the upperend of the member K through which air passes from the air chamberCtoQt-.he main ies rections is limited by one or more stops 16 formed preferably by a screw or screws that project inwardly from the side wall of the passageway A into an annular groove 17 in the exterior of the member L, but I Wish it to be understood that Various other means can 'be used for increasing the supply of air from the air chamber to the main passageway A of the carburetor without departing from the spirit of my invent-ion.

Air openings 18 are formed in the sleeve 5 adjacent the contracted portion of the Siphoning device K, so as .to admit air to the accelerating well and to the annular space at the upper end of the member J, and a plurality of vertically-disposed slots 19 are formed in the lower end portion of the member J, so as to admit air and liquid fuel to the interior of said member, from the accelerating well, said slots extending upwardly from the bottom of the accelerating well G.

As previously stated, the tube or by-pass 2 supplies fuel to the main passageway A when the motor is idling and alsowhen the throttle valve is partly open, the particular period in the cycle of opera-tions of the carburetor when the tube 2 goes out of service, or, in other words, when said tube ceases to supply fuel to the passageway A, varying, Usually, however, the tube 2 will go out of service wheri approximately 10% of the capacity of the carburetor is reached. From this point on, the fuel in the accelerating well G and the fuel discharged from thenozzle I constitutes the source of supply of fuel for the main passageway A. After the throttle valve has reached such a position that the tube 2 ceases to supply'fuel toA the passageway A, the air that is drawn upwardly into said passageway through the annular opening beenough to cause air to be drawn inwardly,

tween the upper end of the tubular member K and the contracted portion of the tubular member Ii, which, at this time is in the position shown in Figure 2, creates a suction inside of the bottom tubular member J of sufficient intensity to draw air inwardly through the openings 18 in the sleeve 5, thence downwardly into the well G and through the vertically-disposed slots 19 in the lower end of the member J, and thereafter, upwardly through said member J, thus causing more or less of the fuel in the well G to be absorbed bythe air and carried upwardly into the main passageway A. When the throttle valve reaches such a position as to cause sufficient air to travel through the well G to keep said well dry, the suction inside of the intermediate tubular member K becomes strong through the openings 18 in the sleeve' 5, and thence upwardly through the annular space ,between lthe upper end of the tubular member J and the lower endof the intermediate tubular member K. The air that rushes upwardly through said annular space increases the suction inside of the bottom tubular membcr J, and causes fuel to be drawn from the nozzle I and carried upwardly into the main passageway A.

lUp to this stage of speed the carburetor functions as a small capacity carburetor, but

the movement of the throttle valve B into its wide open position automaticallyconverts the carburetor into a large capacity carburetor by permitting the motor to increase the supply of air through the main passageway A and simultaneously increase the supply of liquid fuelto said main passageway A. The increase in the supply'of air to said passageway is obtained by mounting the siphoning device L in the pass A eway A\.in such a manner that the inrush o air into the passageway A causes the member L to move upwardly away lfrom the upper end of the member K, as'previously described, thereby increasing the size of the opening through which air is admitted to the passageway A' from the air chamber C. The increase in the supply of liquid fuel to the main passageway A is obtained by exerting a stronger suction on the fuel nozzle I and also by causing .air to be admitted to the center duct or passageway 13 of said nozzle, so as to speed up the flow of the fuel that travels upwardly through said nozzle, it being a well established fact that a stream of liquid fuel which contains some air will travel at a higherspeed than a solid stream of liquid fuel, assuming, of course, that both streams are subjected to a suction of the same degree or intensity. In the form of my invention herein illustrated the admission-of air to the center duct or passageway 13of the fuel nozzle I is obtained by 'drawing air Vdownwardly through the duct 14, and thence upwardly through the contracted portion 13 of the center passageway of the fuel nozzle, which action is produced by increasing thesuction that is exerted on bottom tubular member J. At this time air is y also rushing upwardly around the upper end of the fuel nozzle, the air that rushes upwardly past the end of the nozzle being admitted to the interior of the lower end portion of the bottom tubular member J through the vertical slots 19 in same.-

From the foregoing it will be seen that in a carburetor of the construction above described there is one stage' in which the air that rushes upwardly around the upper end ofthe tubular member K produces sutlicient suction inside of said member to cause. air totravel through the accelerating well G and keep said well dry; there is another stage in which the air that rushes upwardly around the upper end of the bottom tubular member J produces sufficient suction inside of said member J to cause fuel to be drawn from the nozzle I and discharged upwardly into the main passageway A; and there is 5. tion on the center duct 13 of saidV nozzle and also causes airto break into `or mix with the streamI of liquid fuel that is `flowing up` wardly vthrough said center duct.

Whenjthe throttle valve is moved Aback towards its closed position the tubular memi tion,

, arranged transversely ber L in the main passageway A dropsback to its normal position shown in Figure 2, thereby concentrating the suction on the 'tubular members which are arranged in a lower plane and causing said lower tubular members to 'draw fuel until the throttle valvereaches a position where the by-pass 2 begins to deliver fuel, and continuing untilthe throttle valve reaches its position set for idle. `By equipping the carburetor with elements of the kind and arrangement above described I obtain a carburetor of small cfapacity when the tubular member L is V-in its lower. position and the-bypass 2 is func- ""tioning, and I obtain acarbiiretorgof great capacity when the tubular member 'L is in its high position and ,the infl'iltiple Siphon ingdevices are functioning to deliver fuel in an advance relationto the How of air. To put it in another way, 'whenthethrottle valve is moved back-towards its closed posit'he flow of gas through the carburetor diminishes, andl for lackx of support, the tubular member L drops downwardly towards its position of rest' shown in Figure 2; The annular passage between the lowernn of the member L and the top of the intermediate member K being ,.vreduced, the diminished iiow f gas is concentrated in the annular space between K and J, and between J and the nozzle I, `to, thus maintain a more .robust activity at these critical points an compensate for` the fuel fiow to lag behind the air flow as the suction diminishes. As the throttle .valveIcontinues to move towards its closed." position, the upwardy How of air between the upper end of the tubular ,member J andthecontracted portion of the y `intermediate .member K ceases, and when the throttlevalveis near its idling position, the fuel tube or by-pass 2 comes into service and supplies fuel directly to the main passageway A at a point in proximity to the throttle valve.v

It is necessary. that the contracted portion 13 of the fuel duct 13 of the nozzle I be of very small diameter, so that said nozzle will not supply too much fuel when the throttle valve is in its wide open. position, and in order to prevent the contracted portion ofv becoming cloggcdby the lint that are invariably and which might become across the lower end said duct 13 from small particles of present in gasolene,

55 of a small bore duct of uniform diameter of the fuel. passageway of the nozzle I, the

suction atthe upper end of the nozzle will cause said particles of lint or thelike to fold or double up in the flared inlet portion 13b of the fuel duct of the nozzle and then travel upwardly .through the contracted portion of said fuel duct, with the fuel. The cross duct 15, in t-he nozzle I enables the diameter of the contracted portion 13a ofthe center duct 13 of `the nozzle to'be made larger than would be possible if-the cross duct 15 were omitted, due,of course, 4to `the fact that the hir which is drawn inwardly through said cross duct reduces the suction that is created yon thel contracted portion 13a.

tle. will cause the fuel in said well to be dumped into the main passageway of the carburetor, andl a. slow or gradual opening of the' throttle will'cause the fuel in the accelerating well tofbe discharged gradually and 'economically through a path separate and dist-inet. from that through which the fuel escapes from the accelerating well on a sudden opening of the throttle. In the form of my invention herein illustrated the sudden discharge of the fuel from the accelerating `well`,hor the dumping of said fuel into the main passageway of the carburetor, is effected by forming vertically-disposed slots 19 in the .lower end portion of the tubular member J that surrounds the fuel nozzle. When the d throttle lis opened suddenly, the air that rushes do nwardly into the acceleratingwell picks up. t e fuel in said well and carries it inwardly through the slots 19 inthe tubular 1n mber J, and thence upwardly through-said tu ular member into the main passageway A. The gradual and economical discharge of the fuel from the accelerating well is effected by arrangingthe duct 14 at the lower end of the accelerating well in 4such`a way that it establishes communication between said well and the lower end of the center passageway 13 of the `fuel nozzle. When the throttle is opened gradually, the steady suction that is exerted on'the upper end of the fuel nozzle causes the fuelin the accelerating well lto be drawn slowly or gradually, downwardly ,through the duct 14, and thence upwardly through the center 'passageway of the fuel nozzle; Consequently, a carburetor of the construction above described is distinguished from conventional `carburetors of the type that are equipped with accelerating wells, inl ythat two pat-hs are provided for the escape As previously stated,one object of my in# gradually, which, of course,

of thev fuel from the accelerating well, one path being so constructed that the fuel can escape rapidly, practically in one large gulp, to use a homely phrase, and the-"other path being so constructed that `the fuel will escape adds greatly to the economy of the carburetor.

A carburetor of the construction above described is exceptionally efficient and economical and lis particularly 4adapted for use on high speed, small bore, six-cylinder motors,

` speeds and functions as due to the fact that it functions as a small capacity carburetor at ordinaryrunning a large capacity carburetor at high s eeds, notwithstanding the fact that the fuel) nozzle' has a fixed orifice -or duct. The carburetor is easy to adjust,

it is reliable in operation and it is of such design that there are no abrupt variations in the fuel supply between successive stages of s ed of the motor. In addition to the desira le features above pointed out, the carburetor labove described is inexpensive to manufacture, as 1t is composed of arelatively small number of parts that can be producedV by simplemachine operations and thereafter j assembled easily.

Havlng thus ldescribed myinvention, w-hat I claim asnew and desire to secure by Letters Patent of the United States is:

1. A carburetor for an internal combustion motor, provided with a main passageway through which a mixture of fuel and air travels to the intake of the motor, a throttle valve for said main passageway, an accelerating well for holding fuel, means for causing the fuel in said well to be dumped into said main passageway when the throttle is opened suddenl and a separateand distinct means for causlng the fuel to be discharged from said well into the main passageway gradually and economically when the throttle is opened gradually. .i

2. A carburetor for an internal combustion motor, provided with a main `passageway Vthrough which va mixture of fuel and air travels to the intake of the motor, a throttle 'throttle Vcauses the fuel in sai gradually into said main passageway.

Valve for said main passageway, an acceleraccelerating well for holding fuel, a tubular memberlleading from said well and arranged so as to discharge into saidlmain passageway, a shiftable member in the main passageway that co-operates with the upper end of said tubular member to forma variable air inlet for the main passageway that is always open, and two separate and distinct paths through which the fuel in the accelerating well can travel from said well into said main passageway, one of said paths being of considerably greater cross-sectional' area than the other so as to permit the fuel in the accelerating .f

well to vbe discharged fromsame quickly by a sudden openin of the throttle or discharged gradual y by slowly opening the throttle.

4. A carburetor for an internal combustion motor, provided with a main passageway throughwhich a mixture of fuel and air travels to the intake of the motor, a throttle valve in said passageway, means for supplying fuel to said passageway above the throttle valve for idle speeds, a fuel nozzle arranged so as to discharge fuel towards said passageway, a tubular element arranged in concentric relation with said nozzle and provided intermediate its ends with an air inlet, a shiftable member way operated by the suction of that co-operates tubular element for said main atin well for holding fuel, two se arate and distinct paths of traveLforthe'fue from said well to said passageway, one of said paths beingy so proportioned that the 4fuel will travel through same freely when the throttle is openedsuddenly and the other belng so proportioned that a gradual o ning of the 3. A carburetor l"for'an internal combus- I 4tion motor, provided with a main-,passageway through which fuel and air travel to the intake of the motor, a throttle valve for said main passageway, an idle feed fuel supplying means for delivering fuel to sald passageway above the throttle valve, an I'lair chamber Iprovided with a fixed air inlet, an

well. to pass in said main passage- 

